1. Field of the Invention
The present invention relates to a stator for use in rotary electric machines such as electric motors and generators, and a stator manufacturing method.
2. Description of the Related Art
Conventionally, stators 1 for use in rotary electric machines such as electric motors and generators include those comprising a stator core 2 as shown in the plan view of FIG. 11. The stator core 2 comprises a core back core 3 formed in an approximately annular shape, and a plurality of teeth cores 4 disposed radially on the core back core 3. Stator winding 6 are wound around the side surfaces of these teeth cores 4 to form the stator 1.
However, in order to prevent excess current from flowing through the teeth cores 4, it is necessary to ensure insulation between the stator windings 6 and the teeth cores 4. Consequently, insulation between the stator windings 6 and the teeth cores 4 is conventionally ensured by providing insulating sheets 7 and 8 such as those shown in FIGS. 12A to 12D, for example.
Specifically, first, the approximately U-shaped insulating sheet 7 is disposed so as to cover the side surfaces of adjacent teeth cores 4 and the inner surface of the core back core 3 (see FIGS. 12A and 12B). Next, the stator windings 6 are wound on the teeth cores 4, the side surfaces of which are covered by the insulating sheet 7 (see FIG. 12C). The approximately flat insulating sheet 8 is then inserted into a slot 5 between the adjacent teeth cores 4 and fitted tightly against the approximately U-shaped insulating sheet 7, thereby sealing the stator windings 6 within the slot 5 (see FIG. 12D). By employing such a construction, insulation between the stator windings 6 and the teeth cores 4 can be ensured. To ensure that the approximately flat insulating sheet 8 is capable of this sealing action, the insulating sheet 8 has a greater thickness than the approximately U-shaped insulating sheet 7.
However, in the related art described above, because the winding of the stator windings and the positioning of the insulating sheets are performed inside the locations of the teeth cores, work space for the equipment (not shown in the figure) which performs the winding or positioning must be made available on the inside of the positioning sites. Consequently, a problem occurs in that the extent to which the stator windings can be wound on the teeth cores is restricted by the space required by this equipment, and the space factor is reduced accordingly.
In addition, in the related art described above, the use of two different types of insulating sheets, which differ in shape and thickness within each of the slots between adjacent teeth cores is problematic in that the number of components increases. Furthermore, because the assembly of the two types of insulating sheet must be performed in separate processes, the manufacturing process becomes complicated.
In accordance with these circumstances, an object of the present invention is to provide a stator and a stator manufacturing method in which the space factor can be improved, while reducing the number of components and simplifying the manufacturing process.
In order to resolve the problems described above, a first aspect of the present invention provides a stator (for example, a stator 10 of the embodiment) comprising a plurality of teeth cores (for example, teeth cores 11 of the embodiment) positioned at predetermined intervals on a predetermined circumference, a core back core (for example, a core back core 12 of the embodiment) provided on a circumferential outside between adjacent teeth cores, and stator windings (for example, stator windings 13 of the embodiment) which are wound around the teeth cores, wherein an approximately U-shaped insulating sheet (for example, an insulating sheet 14 of the embodiment) is provided between adjacent teeth cores with the ends of the sheet facing towards the circumferential outside, the insulating sheet is provided between the teeth cores and the stator windings, and the ends of the insulating sheet are bent inward and sealed off by an inner end surface of the core back core which is inserted from the circumferential outside.
By employing the above construction, it is possible to position the insulating sheet from the circumferential outside, once the plurality of teeth cores have been positioned on the predetermined circumference. Consequently, the operation of positioning the insulating sheet can be performed from the circumferential outside, and it is consequently no longer necessary to reserve space for performing the positioning operation on the circumferential inside. Furthermore, in a similar manner, the core back core can be inserted between and connected with the adjacent teeth cores from the circumferential outside, and consequently it is not necessary to reserve space on the circumferential inside for the core back core connection operation. Accordingly, because the space between the teeth cores for winding the stator windings can be increased, the space factor can be improved.
Furthermore, because the approximately U-shaped insulating sheet is provided in each slot between adjacent teeth cores, and the ends of the insulating sheet are bent inward and sealed off by the inner end surface of the core back core, it is possible to ensure insulation between the stator windings and the teeth cores using a single insulating sheet for each slot. Consequently, the number of components can be reduced when compared with conventional examples because the number of insulating sheets is reduced by half. Moreover because the operation of inserting the core back core and the operation of sealing off the insulating sheet can be performed simultaneously, the manufacturing process can be simplified.
A second aspect of the present invention is a stator wherein there is provided a bending section (for example, a bending section 15 in the embodiment) formed by bending an end of the U-shaped insulating sheet inward between the teeth cores. By employing the above construction, the ends of the approximately U-shaped insulating sheet are reliably bent and sealed off when the core back core is inserted, and consequently the formability can be improved.
A third aspect of the present invention is a stator wherein a guide recess (for example, a guide recess 16 of the embodiment) which guides the ends of the insulating sheet is provided on an inner end surface of the core back core.
By employing the above construction, the ends of the approximately U-shaped insulating sheet are guided and bent inwards by the guide recess when the core back core is inserted, and are more reliably sealed off, and consequently the formability can be even further improved.
A fourth aspect of the present invention is a stator manufacturing method wherein by positioning a plurality of teeth cores at predetermined intervals on a predetermined circumference, providing an approximately U-shaped insulating sheet between adjacent teeth coreso that the ends thereof are facing towards a circumferential outside, windingtator winding around the teeth cores on which the approximately U-shaped insulating sheet is provided, and inserting a core back core between adjacent teeth cores from the circumferential outside, both ends of the approximately U-shaped insulating sheet are bent over and sealed off.
By employing the above construction, the space factor can be improved, the number of components can be kept to a minimum, and the manufacturing process can be simplified.